Intervertebral disc device employing prebent sheath

ABSTRACT

An intervertebral disc device is provided comprising a distal sheath sized to be extended from a distal end of an introducer that is percutaneously delivered into an interior of an intervertebral disc, a distal section of the sheath being predisposed to adopting a bent configuration when extended from the introducer; a probe adapted to be extended from a distal end of the sheath, the bent section of the sheath causing the probe to adopt a same bent configuration; and a proximal handle for externally guiding the probe within an intervertebral disc.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to methods and apparatuses for accessingand modifying intervertebral disc tissue and more particularly toaccessing and modifying intervertebral disc tissue using percutaneoustechniques that avoid major surgical intervention.

[0003] 2. Description of Related Art

[0004] Intervertebral disc abnormalities have a high incidence in thepopulation and may result in pain and discomfort if they impinge on orirritate nerves. Disc abnormalities may be the result of trauma,repetitive use, metabolic disorders and the aging process and includesuch disorders but are not limited to degenerative discs (i) localizedtears or fissures in the annulus fibrosus, (ii) localized discherniations with contained or escaped extrusions, and (iii) chronic,circumferential bulging disc.

[0005] Disc fissures occur rather easily after structural degeneration(a part of the aging process that may be accelerated by trauma) offibrous components of the annulus fibrosus. Sneezing, bending or justattrition can tear these degenerated annulus fibers, creating a fissure.The fissure may or may not be accompanied by extrusion of nucleuspulposus material into or beyond the annulus fibrosus. The fissureitself may be the sole morphological change, above and beyondgeneralized degenerative changes in the connective tissue of the disc.Even if there is no visible extrusion, biochemicals within the disc maystill irritate surrounding structures. Disc fissures can bedeabilitatingly painful. Initial treatment is symptomatic, including bedrest, pain killers and muscle relaxants. More recently spinal fusionwith cages have been performed when conservative treatment did notrelieve the pain. The fissure may also be associated with a herniationof that portion of the annulus.

[0006] With a contained disc herniation, there are no free nucleusfragments in the spinal canal. Nevertheless, even a contained discherniation is problematic because the outward protrusion can press onthe spinal nerves or irritate other structures. In addition to nerveroot compression, escaped nucleus pulposus contents may chemicallyirritate neural structures. Current treatment methods include reductionof pressure on the annulus by removing some of the interior nucleuspulposus material by percutaneous nuclectomy. However, complicationsinclude disc space infection, nerve root injury, hematoma formation,instability of the adjacent vertebrae and collapse of the disc fromdecrease in height.

[0007] Another disc problem occurs when the disc bulges outwardcircumferentially in all directions and not just in one location. Overtime, the disc weakens and takes on a “roll” shape or circumferentialbulge. Mechanical stiffness of the joint is reduced and the joint maybecome unstable. One vertebra may settle on top of another. This problemcontinues as the body ages and accounts for shortened stature in oldage. With the increasing life expectancy of the population, suchdegenerative disc disease and impairment of nerve function are becomingmajor public health problems. As the disc “roll” extends beyond thenormal circumference, the disc height may be compromised, foramina withnerve roots are compressed. In addition, osteophytes may form on theouter surface of the disc roll and further encroach on the spinal canaland foramina through which nerves pass. The condition is called lumbarspondylosis.

[0008] It has been thought that such disc degeneration creates segmentalinstability which disturbs sensitive structures which in turn registerpain. Traditional, conservative methods of treatment include bed rest,pain medication, physical therapy or steroid injection. Upon failure ofconservative therapy, spinal pain (assumed to be due to instability) hasbeen treated by spinal fusion, with or without instrumentation, whichcauses the vertebrae above and below the disc to grow solidly togetherand form a single, solid piece of bone. The procedure is carried outwith or without discectomy. Other treatment include discectomy alone ordisc decompression with or without fusion. Nuclectomy can be performedby removing some of the nucleus to reduce pressure on the annulus.However, complications include disc space infection, nerve root injury,hematoma formation, and instability of adjacent vertebrae.

[0009] These interventions have been problematic in that alleviation ofback pain is unpredictable even if surgery appears successful. Inattempts to overcome these difficulties, new fixation devices have beenintroduced to the market, including but not limited to pedicle screwsand interbody fusion cages. Although pedicle screws provide a highfusion success rate, there is still no direct correlation between fusionsuccess and patient improvement in function and pain. Studies on fusionhave demonstrated success rate of between 50% and 67% for painimprovement, and a significant number of patients have more painpostoperatively. Therefore, different methods of helping patients withdegenerative disc problems need to be explored.

[0010] One of the challenges associated with treating intervertebraldiscs is accessing them via percutaneous methods. To appreciate thedifficulty presented, the anatomical structure of the spine and anintervertebral disc is illustrated and described below.

[0011]FIGS. 1A and 1B illustrate a cross-sectional anatomical view of avertebra and associated disc and a lateral view of a portion of a lumbarand thoracic spine, respectively. Structures of a typical cervicalvertebra (superior aspect) are shown in FIG. 1A: 104—lamina; 106—spinalcord; 108—dorsal root of spinal nerve; 114—ventral root of spinal nerve;116—posterior longitudinal ligament; 118—intervertebral disc;120—nucleus pulposus; 122—annulus fibrosus; 124—anterior longitudinalligament; 126—vertebral body; 128—pedicle; 130—vertebral artery;132—vertebral veins; 134—superior articular facet; 136—posterior lateralportion of the annulus; 138—posterior medial portion of the annulus; and142—spinous process. In FIG. 1A, one side of the intervertebral disc 118is not shown so that the anterior vertebral body 126 can be seen.

[0012]FIG. 1B is a lateral aspect of the lower portion of a typicalspinal column showing the entire lumbar region and part of the thoracicregion and displaying the following structures: 162—intervertebral disc;142—spinous process; 168—inferior articular process; 170—inferiorvertebral notch; 174—superior articular process; 176—lumbar curvature;and 180—sacrum.

[0013] The presence of the spinal cord and the posterior portion of thevertebral body, including the spinous process, and superior and inferiorarticular processes, prohibit introduction of a needle or trocar from adirectly posterior position. This is important because the posteriordisc wall is the site of symptomatic annulus tears and discprotrusions/extrusions that compress or irritate spinal nerves for mostdegenerative disc syndromes.

[0014]FIG. 1C provides a posterior-lateral anatomical view of two lumbarvertebrae and illustration of the triangular working zone. The inferiorarticular process 168, along with the pedicle 128 and the lumbar spinalnerve 110, form a small “triangular” window through which introductionof an instrument can be achieved from the posterior lateral approach.FIG. 1D illustrates an instrument (an introducer 169) introduced into anintervertebral disc by the posterior lateral approach.

[0015]FIG. 1E illustrates the anatomy of an intervertebral disc ingreater detail and shows an introducer 169 inserted into the disc.Structures of the disc are identified and described by these anatomicaldesignations: the posterior lateral inner annulus 136, posterior medialinner annulus 138, annulus fibrosus 122/nucleus pulposus 120 interface,the annulus/dural interface 146, annulus/posterior longitudinal ligamentinterface 148, anterior lateral inner annulus 150, and the anteriormedial inner annulus 152.

[0016] The annulus fibrosus 122 is comprised primarily of tough fibrousmaterial, while the nucleus pulposus 120 is comprised primarily of anamorphous colloidal gel. There is a transition zone between the annulusfibrosus 122 and the nucleus pulposus 120 made of both fibrous-likematerial and amorphous colloidal gel. The border between the annulusfibrosus 122 and the nucleus pulposus 120 becomes more difficult todistinguish as a patient ages, due to degenerative changes. This processmay begin as early as 30 years of age. For purposes of thisspecification, the inner wall of the annulus fibrosus can include theyoung wall comprised primarily of fibrous material as well as thetransition zone which includes both fibrous material and amorphouscolloidal gels (hereafter collectively referred to as the “inner wall ofthe annulus fibrosus”). Functionally, the location at which there is anincrease in resistance to probe penetration and which is sufficient tocause bending of the distal portion of the probe into a radius less thanthat of the internal wall 22 of the annulus fibrosus is considered to bethe “inner wall of the annulus fibrosus”.

[0017] As with any medical instrument and method, not all patients canbe treated, especially when their disease or injury is too severe. Thereis a medical gradation of degenerative disc disease (stages 1-5). See,for example, Adams et al., “The Stages of Disc Degeneration as Revealedby Discograms,” J. Bone and Joint Surgery, 68, 36-41 (1986). As thesegrades are commonly understood, the methods of instrument navigationdescribed herein would probably not be able to distinguish between thenucleus and the annulus in degenerative disease of grade 5. In any case,most treatment is expected to be performed in discs in stages 3 and 4,as stages 1 and 2 are asymptomatic in most patients, and stage 5 mayrequire disc removal and fusion.

[0018] It is well known to those skilled in the art that percutaneousaccess to the disc is achieved by placing an introducer into the discfrom this posterior lateral approach, but the triangular window does notallow much room to maneuver. Once the introducer pierces the toughannulus fibrosus, the introducer is fixed at two points along its lengthand has very little freedom of movement. Thus, with the exception ofdevices such as those described in U.S. Pat. Nos. 6,135,999; 6,126,682;6,122,549; 6,099,514; 6,095,149; 6,073,051; 6,007,570; 5,980,504 (whichare each incorporated herein by reference), the posterior lateralapproach has only allowed access to small central and anterior portionsof the nucleus pulposus.

[0019] The present invention provides devices and methods which aredesigned to more efficiently access and treat the interior ofintervertebral discs by the posterior lateral approach.

SUMMARY OF THE INVENTION

[0020] The present invention relates to various embodiments ofintervertebral disc devices and their methods of use.

[0021] According to one embodiment, the intervertebral disc devicecomprises a distal probe sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the probe comprising a flexibleneck which tapers in a proximal to distal direction, and a distal tipwhich is larger in cross sectional diameter than the flexible neckadjacent the distal tip, the flexible neck and distal tip serving toprevent the probe distal end from piercing an internal wall of theintervertebral disc; and a proximal handle for externally guiding theprobe within an intervertebral disc.

[0022] The flexible neck may optionally be designed such that it is notpredisposed to bending in any direction relative to a longitudinal axisof the probe. Alternatively, the flexible neck may be designed to bepredisposed to bending along a single plane relative to a longitudinalaxis of the probe. Alternatively, the flexible neck may be designed tobe predisposed to bending in opposing directions along a single planerelative to a longitudinal axis of the probe. Alternatively, theflexible neck may be designed to be predisposed to bending in at leasttwo different directions along at least two different planes relative toa longitudinal axis of the probe.

[0023] According to this embodiment, the flexible neck may optionallyhave a round cross section. Alternatively, or in addition, the flexibleneck may optionally have at least one flat surface extending along alongitudinal axis of the neck. In one variation, the flexible neck hastwo flat surfaces extending along a longitudinal axis of the neck onopposing sides of the neck.

[0024] Also according to this embodiment, the neck may optionally beformed of a flexible coil.

[0025] According to this embodiment, the distal tip may optionally havea larger cross sectional diameter than a largest cross sectionaldiameter of the flexible neck. The distal tip may be symmetrical orasymmetrical. In certain variations, the distal tip is dome shaped orhas a flat surface perpendicular to a longitudinal axis of the probe.

[0026] The distal tip may be attached to the neck of the probe by avariety of mechanisms including, for example, a spring or a pivotmechanism such as a ball and socket mechanism.

[0027] In one preferred variation, the flexibility of the neck of theprobe is designed such that it causes the probe to bend and the distaltip to trail behind a portion of the probe as the probe is advancedthrough tissue within an intervertebral disc. The shape of the distaltip may also contribute to the distal tip trailing behind a portion ofthe probe.

[0028] In another embodiment, an intervertebral disc device is providedcomprising: a distal probe sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the probe comprising an activeelectrode and a return electrode which are each spirally wrapped aroundthe probe such that there are multiple alternating bands of the sameactive and return electrodes positioned longitudinally along the lengthof the distal section of the probe, the active and return electrodesbeing adapted to deliver bipolar electromagnetic energy to tissue withinthe intervertebral disc; and a proximal handle for externally guidingthe probe within an intervertebral disc.

[0029] According to this embodiment, the distal section of the probe maybe predisposed to forming a loop.

[0030] In another embodiment, an intervertebral disc device is providedcomprising: a distal probe sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the probe being predisposed toforming a loop when extended from the distal end of the introducer, thelooping portion of the probe comprising an active electrode and a returnelectrode which are positioned on the probe such that the active andreturn electrodes are on opposing sides of the probe loop; and aproximal handle for externally guiding the probe within anintervertebral disc.

[0031] In yet another embodiment, an intervertebral disc device isprovided comprising: a distal probe sized to be extended from a distalend of an introducer that is percutaneously delivered into an interiorof an intervertebral disc, a distal section of the probe comprisingseparate active and return electrode elements which are predisposed tobending away from each other when extended from the distal end of theintroducer; and a proximal handle for externally guiding the probewithin an intervertebral disc.

[0032] In another embodiment, an intervertebral disc device is providedcomprising: a distal sheath sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the sheath being predisposed toadopting a bent configuration when extended from the introducer; a probeadapted to be extended from a distal end of the sheath, the bent sectionof the sheath causing the probe to adopt a same bent configuration; anda proximal handle for externally guiding the probe within anintervertebral disc.

[0033] In another embodiment, an intervertebral disc device is providedcomprising: a distal sheath sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the sheath being predisposed toadopting a bent configuration when extended from the introducer; a guidewire adapted to be extended from a distal end of the sheath, the bentsection of the sheath causing the guide wire to adopt a same bentconfiguration; a probe adapted to be extended from a distal end of thesheath over the guide wire, the bent section of the sheath causing theprobe to adopt a same bent configuration; and a proximal handle forexternally guiding the probe within an intervertebral disc.

[0034] According to one variation of this embodiment, a distal sectionof the probe comprises an active electrode and a return electrode whichare each spirally wrapped around the probe such that there are multiplealternating bands of the same active and return electrodes positionedlongitudinally along the length of the distal section of the probe, theactive and return electrodes being adapted to deliver bipolarelectromagnetic energy to tissue within the intervertebral disc.Optionally, the distal section of the probe may be predisposed toforming a loop. When the distal section of the probe is predisposed toforming a loop when extended from the distal end of the introducer, thelooping portion of the probe may comprise an active electrode and areturn electrode which are positioned on the probe such that the activeand return electrodes are on opposing sides of the probe loop.

[0035] According to another variation of this embodiment, a distalsection of the probe comprises separate active and return electrodeelements which are predisposed to bending away from each other whenextended from the distal end of the introducer.

[0036] In another embodiment, an intervertebral disc device is providedcomprising: a probe capable of being extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, the probe forming a loop when extended from thedistal end of the introducer, the loop having first and second proximalends external to the introducer which are brought together adjacent theintroducer distal end to form the loop by the proximal ends being eitherattached to or entering the distal end of the introducer; and a proximalhandle for externally causing the probe to be extended from the distalend of the introducer and externally guiding the probe within anintervertebral disc.

[0037] According to this embodiment, the device may optionally furtherinclude an introducer, the first proximal end of the probe beingattached to the introducer adjacent a distal end of the introducer, thesecond proximal end of the probe being extendable from the introducerdistal end to form the loop. According to this variation, the firstproximal end of the probe may optionally be attached to the introduceradjacent the distal end of the introducer by a guide wire lead.Alternatively, the first and second proximal ends of the probe may eachbe separately extendable from the introducer distal end to form theloop. When the first and second proximal ends of the probe are eachseparately extendable from the introducer distal end to form the loop,the first and second proximal ends of the probe may have different crosssectional geometries. According to this variation, the different crosssectional geometries of the first and second proximal ends may beselected such that the cross sectional geometry of the first proximalend is a compliment of the cross sectional geometry of the secondproximal end.

[0038] In another embodiment, an intervertebral disc device is providedcomprising: a guide wire capable of being extended from a distal end ofan introducer that is percutaneously delivered into an interior of anintervertebral disc, the guide wire forming a loop when extended fromthe distal end of the introducer, the loop having first and secondproximal ends external to the introducer which are brought togetheradjacent the introducer distal end to form the loop by the proximal endsbeing either attached to or entering the distal end of the introducer; aprobe capable of being extended over the guide wire from the distal endof the introducer; and a proximal handle for externally causing theguide wire and probe to be extended from the distal end of theintroducer and externally guiding the guide wire and probe within anintervertebral disc.

[0039] In one variation of this embodiment, the device further includesan introducer, the first proximal end of the guide wire being attachedto the introducer adjacent a distal end of the introducer, the secondproximal end of the guide wire being extendable from the introducerdistal end to form the loop. In another variation, the first and secondproximal ends of the guide wire are each separately extendable from theintroducer distal end to form the loop.

[0040] In another embodiment, an intervertebral disc device is providedcomprising: guide wire capable of being extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the guide wire beingpredisposed to forming a loop when extended from the distal end of theintroducer, the looped distal section of the guide wire serving tolocalize the looped distal section within the intervertebral disc; aprobe capable of being extended over the guide wire from the distal endof the introducer, the probe and guide wire being extendable incombination such that position of the looped distal section of the guidewire is not changed; and a proximal handle for externally causing theguide wire and probe to be extended from the distal end of theintroducer and externally guiding the guide wire and probe within anintervertebral disc.

[0041] According to any of the above embodiments, the device may furtherinclude flexible tubing operably interconnecting the proximal handlewith the distal probe. The probe and/or guide wire may optionally extendwithin the flexible tubing to the handle.

[0042] Also according to any of the above embodiments, the device mayfurther include a connector system which enables an introducer to beremoveably attached to the connector system, the probe beingpositionable within the introducer for delivery within theintervertebral disc with the assistance of the introducer.

[0043] According to any of the above embodiments, the device may furtherinclude a probe or guide wire with a mechanism for securing the probe orguide wire within the selected section of the intervertebral disc. Themechanism may be a curved portion adjacent the distal end capable ofanchoring the probe or guide wire into tissue. The curved distal portionpreferably forms a distal end of the probe or guide wire. The curveddistal portion is optionally retractable and optionally divides intomultiple separate curved portions, such as to form a treble hook.

[0044] Also according to any of the above embodiments, the probe mayfurther include a functional element which performs a function. A widevariety of functions may be performed by the functional elementincluding, but not limited to, transmitting energy to tissue within anintervertebral disc, delivering material to within an intervertebraldisc, and removing material within an intervertebral disc.

[0045] When the function element transmits energy, the probe may furtherinclude an electromagnetic energy device capable of supplying energywithin the intervertebral disc. The electromagnetic energy device may becapable of delivering energy selected from group consisting of coherentand incoherent light and radiofrequency (RF), microwave, and ultrasoundwaves. When delivering RF energy, the electromagnetic energy devicecomprises electrodes adapted to deliver RF energy. The RF electrodes mayadopt a monopolar or bipolar configuration. The electromagnetic energydevice may also comprise a resistive heating mechanism.

[0046] Also according to any of the above embodiments, the handle mayfurther comprise a probe control element for controlling the movement ofthe probe adjacent a distal end of the device. The device may alsocomprise a guide wire control element for controlling the movement ofthe guide wire adjacent a distal end of the device.

[0047] Methods are also provided for employing the various devices ofthe present invention to treat an interior of an intervertebral disc.

[0048] In one embodiment, the method comprises inserting an introducerthrough a skin of a person such that the distal end of the introducertravels within the person via a posterior lateral approach to anintervertebral disc such that a distal end of the introducer ispositioned in or adjacent an intervertebral disc; extending a probe froma distal end of the introducer such that the probe is positioned withinthe intervertebral disc; and treating tissue within the interior of theintervertebral disc using the probe. The probe that is extended from theintroducer may have any of the various probe designs described herein.

[0049] In another embodiment, the method comprises inserting anintroducer through a skin of a person such that the distal end of theintroducer travels within the person via a posterior lateral approach toan intervertebral disc such that a distal end of the introducer ispositioned in or adjacent an intervertebral disc; extending a guide wirefrom a distal end of the introducer such that the guide wire ispositioned within the intervertebral disc; extending a probe over theguide wire, and treating tissue within the interior of theintervertebral disc using the probe. The guide wire and probe that areextended from the introducer may have any of the various guide wire andprobe designs described herein.

[0050] In another embodiment of the invention, a method for delivering aprobe is provided. The method comprises extending a guide wire into aintervertebral disc such that the guide wire is positioned within theintervertebral disc adjacent an inner wall of the disc; attaching adistal portion of the guide wire to the inner wall; and extending aprobe over the guide wire. The guide wire and probe that are extendedmay have any of the various guide wire and probe designs describedherein.

[0051] According to this embodiment, the step of attaching the distalportion of the guide wire may be accomplished by inserting a portion ofthe guide wire into the tissue of the inner wall of an intervertebraldisc such that the distal portion is held in place and retained by thetissue of the inner wall of the disc. In this reagard, a variety ofattachment mechanisms may be employed. For example, the step ofattaching the distal portion of the guide wire may be by hooking theattachment mechanism into the tissue of the inner wall such that thedistal portion is held in place and retained by the tissue of the innerwall of the disc. The attachment mechanism may be a curved distalportion of the guide wire.

[0052] All of the above embodiments involving attaching the guide wireto the inner wall of an intervertebral disc maybe adapted where theprobe instead of the guide wire comprises an attachment mechanism forattaching the probe to the inner wall.

BRIEF DESCRIPTION OF THE FIGURES

[0053]FIG. 1A provides a superior cross-sectional anatomical view of acervical disc and vertebra.

[0054]FIG. 1B provides a lateral anatomical view of a portion of alumbar spine.

[0055]FIG. 1C provides a posterior-lateral anatomical view of two lumbarvertebrae and illustration of the triangular working zone.

[0056]FIG. 1D provides a superior cross-sectional view of the requiredposterior lateral approach.

[0057]FIG. 1E illustrates the anatomy of an intervertebral disc ingreater detail and shows an introducer inserted into the disc.

[0058]FIG. 2 illustrates an embodiment of an intervertebral disc devicesystem.

[0059]FIG. 3A illustrates a distal section of a probe with a flexibleneck and a blunt distal tip.

[0060]FIG. 3B illustrates a sequence demonstrating the flexing of theflexible neck of the probe.

[0061]FIG. 3C illustrates a distal section of a probe with a roundedneck.

[0062]FIG. 3D illustrates a neck which has been flattened on one side.

[0063]FIG. 3E illustrates a neck which has been flattened on twoopposing sides.

[0064]FIG. 3F illustrates a neck where the neck is formed of a coil.

[0065] FIGS. 4A-4C illustrate a series of different distal tips whichmay be attached to the distal sections of the probes employed in thedevices of the present invention.

[0066]FIG. 4A illustrates a dome shaped distal tip where the distal tipis symmetrical about the longitudinal axis of the distal section of theprobe.

[0067]FIG. 4B illustrates an offset dome shaped distal tip where thedistal tip is asymmetrical about the longitudinal axis of the distalsection of the probe.

[0068]FIG. 4C illustrates an flat distal tip.

[0069] FIGS. 5A-5C illustrate a series of different distal tipattachment mechanisms which may be used to attach a distal tip to adistal section of a probe employed in the devices of the presentinvention.

[0070]FIG. 5A illustrates an embodiment where the distal tip and theneck of the distal section is one unit made of the same material.

[0071]FIG. 5B illustrates an embodiment where the distal tip and theneck of the distal section are attached to each other by a pivotmechanism.

[0072]FIG. 5C illustrates an embodiment where the distal tip and theneck of the distal section are attached to each other by a spring.

[0073]FIG. 6 illustrates movement with bending of a distal sectionwithin nucleous pulposus as the distal section of the device is advancedwithin the intervertebral disc.

[0074] FIGS. 7A-7C illustrate a sequence which shows how tissue forceresisting the forward advancement of the probe within the intervertebraldisc causes the distal section of the probe to bend.

[0075]FIG. 7A shows a probe with an asymmetrical distal tip.

[0076]FIG. 7B illustrates that the asymmetrical resistance causes thedistal section of the probe to bend.

[0077]FIG. 7C illustrates that further bending of the probe causestissue force to be applied to the back of the distal tip as the distalsection is advanced further.

[0078] FIGS. 8A-8Q illustrate a series of different embodiments fordeploying the distal section of the probe from the introducer so thatthe probe approaches the internal wall of the annulus fibrosus.

[0079]FIG. 8A illustrates an embodiment where the distal end of theprobe is attached to the distal end of the introducer.

[0080]FIG. 8B illustrates that the probe shown in FIG. 8A may beextended out of the distal end of the introducer to cause the probe toform a loop.

[0081]FIG. 8C illustrates another embodiment where the distal end of theprobe is attached to the distal end of the introducer via a guide wirelead.

[0082]FIG. 8D illustrates that the probe shown in FIG. 8C may beextended out of the distal end of the introducer to cause the probe toform a loop.

[0083]FIG. 8E illustrates another embodiment where the distal end of theprobe forms a loop within the introducer where both sides of the probeare separately extendable and retractable relative to the distal end ofthe introducer.

[0084]FIG. 8F illustrates that the probe shown in FIG. 8E may beextended out of the distal end of the introducer to cause the probe toform a loop.

[0085]FIG. 8G illustrates another embodiment where a guide wire isattached to the distal end of the introducer.

[0086]FIG. 8I illustrates that the probe shown in FIG. 8G may beextended along the guide wire out of the distal end of the introducer.

[0087]FIG. 8J illustrates another embodiment where a guide wire forms aloop within the introducer where both sides of the guide wire loop areseparately extendable and retractable relative to the distal end of theintroducer.

[0088]FIG. 8K illustrates that extension of the guide wire shown in FIG.8J out of the distal end of the introducer causes the guide wire to forma loop.

[0089]FIG. 8L illustrates that a probe may be extended along the guidewire shown in FIG. 8K out of the distal end of the introducer.

[0090] FIGS. 8M-8O illustrate another embodiment of the embodiment shownin FIG. 8J where the guide wire is capable of being folded upon itself.

[0091]FIG. 8M illustrates the guide wire unfolded where section Aincludes a guide wire with a thin, concave shape, section B includes atapered section that provides an area where the guide wire is foldedupon itself, and section C includes a rounded section such that therounded section fits within the concave shape of section A.

[0092]FIG. 8N shows the cross sections of guide wire sections A-Cillustrated in FIG. 8M.

[0093]FIG. 8O illustrates that the guide wire may be folded upon itselfwhere the crease is at section B, and section A and section C cometogether.

[0094]FIG. 8P provides a sequence illustrating the deployment of theguide wire from an introducer within a disc such that the guide wireencircles the internal wall of the disc.

[0095]FIG. 8Q illustrates yet another embodiment where a guide wire andprobe are used in combination to deploy the probe adjacent an internalwall of a disc.

[0096] FIGS. 9A-9C illustrate one embodiment where a sheath having apredefined curvature adjacent its distal end introduces curvature to aguide wire or probe extended from the sheath.

[0097]FIG. 9A illustrates the distal end of an introducer with a sheathand a probe extending from the introducer.

[0098]FIG. 9B illustrates the sheath being extend from the distal end ofthe introducer.

[0099]FIG. 9C illustrates the probe being extended beyond the sheath.

[0100] FIGS. 10A-10C illustrate a series of preferred designs forthermal energy delivery devices which may be used in combination withthe devices of the present invention.

[0101]FIG. 10A illustrates an embodiment where the thermal energydelivery device is a bipolar electrode comprising an active electrodeand a return electrode where the active and return electrodes are eachspirally wrapped around a portion of the distal section of the probe.

[0102]FIG. 10B illustrates another embodiment of a thermal energydelivery device where the active and return electrodes are positioned onopposing sides of the loop.

[0103]FIG. 10C illustrates another embodiment of a thermal energydelivery device.

[0104]FIGS. 11A and 11B illustrate yet another embodiment for a thermalenergy delivery device which may be used in combination with the devicesof the present invention.

[0105]FIG. 11A illustrates an embodiment where a pair of probes whichform a return electrode and an active electrode extend from anintroducer or sheath and are spaced apart from each other.

[0106]FIG. 11B illustrates a variation on the embodiment shown in FIG.11A where the pair of probes which form an active electrode and returnelectrode diverge from each other adjacent their distal ends.

[0107]FIG. 12 shows an embodiment of the guide wire with an attachmentmechanism at the distal tip for attaching the guide wire to the innerwall of the intervertebral disc.

DETAILED DESCRIPTION

[0108] The present invention provides methods and devices for accessingand treating intervertebral discs. In general, the devices according tothe present invention are externally guidable percutaneousintervertebral disc devices. As such, these devices are used to traversethe patent's skin and access an intervertebral disc through the tissuepositioned between the patient's skin and the intervertebral disc. Entryinto the intervertebral disc is achieved by a posterior lateralapproach.

[0109] 1. Overview of the Intervertebral Disc Treatment Device

[0110]FIG. 2 illustrates an embodiment of an overall system for treatingintervertebral discs which incorporates devices of the presentinvention. It is noted that many of the subcomponents of the devices ofthe present invention, as well as their operation are described infurther detail in U.S. Pat. Nos. 6,135,999; 6,126,682; 6,122,549;6,099,514; 6,095,149; 6,073,051; 6,007,570; 5,980,504, which are eachincorporated herein by reference.

[0111]FIG. 2 depicts but one embodiment of the overall system. It shouldbe noted that systems incorporating the devices of the invention can beprepared in a number of different forms and can consist (for example) ofa single instrument with multiple internal parts or a series ofinstruments that can be replaceably and sequentially inserted into ahollow fixed instrument (such as a needle) that guides the operationalinstruments to a selected location within the intervertebral disc.Because prior patents do not fully agree on how to describe parts ofpercutaneous instruments, terminology with the widest common usage willbe used.

[0112] As illustrated in FIG. 2, the proximal end 210 of the systemcomprises a handle 212 which includes a guide wire control element 214for controlling the movement of a guide wire adjacent a distal end 218of the device and a probe body control element 216 for controlling themovement of a probe (not shown) adjacent the distal end 218 of thedevice. The handle 212 further includes one or more mechanisms 224 (notshown in detail) for attaching different external tools (e.g., energysources, material delivery and removal mechanisms (e.g., a pump),visualization tools, etc.) to the device.

[0113] Flexible tubing 226 attaches the handle 212 to a connector system228 which remains external to the body. As illustrated, the connectorsystem 228 may allow different external tools to be attached to thedevice. In this case a fluid injection tool 232 is depicted. A probe anda guide wire may optionally extend from a distal portion of the devicethrough the flexible tubing to the handle. Alternatively, onlymechanisms for controlling the probe and guide wire may extend from thedistal portion of the device through the flexible tubing to the handle.

[0114] Insertion of flexible tubing between the handle 212 and theconnector system 228 serves to physically isolate movements of thehandle 212 from the portion of the device which is inserted into thepatient. As a result, the patient is less prone to perceive amanipulation of the device within the patient as a result of movement ofthe handle.

[0115] The distal portion of the devices of the present invention may bedelivered through the skin of a patient and into an intervertebral discusing techniques typical of percutaneous interventions. The connectorsystem 228 allows an introducer 230 to be removable coupled to thedevice to facilitate delivery of the distal portion of the devicethrough a patient's skin to within an intervertebral disc. Asillustrated, a luer fitting 234 may be used as the attachment mechanismfor the introducer.

[0116] The term introducer is used herein to indicate that the device ofthe invention can be used with any insertional apparatus that providesproximity to the disc, including many such insertional apparatuses knownin the art. An introducer has an internal introducer lumen with a distalopening 238 at a terminus of the introducer to allow insertion (andmanipulation) of the operational parts of the device into (and in) theinterior of a disc.

[0117] The introducer, in its simplest form, can consist of a hollowneedle-like device (optionally fitted with an internal removableobturator or trocar to prevent clogging during initial insertion) or acombination of a simple exterior cannula that fits around a trocar. Theresult is essentially the same: placement of a hollow tube (the needleor exterior cannula after removal of the obturator or trocar,respectively) through skin and tissue to provide access into the annulusfibrosus. The hollow introducer acts as a guide for introducinginstrumentation. More complex variations exist in percutaneousinstruments designed for other parts of the body and can be applied todesign of instruments intended for disc operations. Examples of suchobturators are well known in the art. A particularly preferredintroducer is a 17- or 18-gauge, thin-wall needle with a matchedobturator, which after insertion is replaced with a probe of the presentinvention.

[0118] The devices of the present invention further include a probe 236which may be extended and retracted relative to the distal opening 238of the introducer 230. For example, a distal section of the probe 236 isshown to be retracted into the introducer in FIG. 2 (above) as well asextended from the distal end of the introducer (below). When extendedfrom the introducer 230, the probe 236 is intended to be located insidethe disc.

[0119] As illustrated in FIG. 1E, the introducer 169 pierces the annulusfibrosus 122 and is advanced through the wall of the annulus fibrosusinto the nucleus pulposus 120. The introducer 169 is extended a desireddistance into nucleus pulposus 120. Once the introducer 169 ispositioned within the nucleus pulposus 120, the distal section of theprobe 236 is advanced through a distal end of introducer 169 intonucleus pulposus 120.

[0120] It is noted that many probe devices access a section of tissue inthe patient's body by being delivered within the lumen of a body vesselsuch as a vein or artery. Although the devices of the present inventionare said to include a probe, the devices of the present invention do notrely upon accessing a section of tissue in the patient's body by beingdelivered within the lumen of a body vessel. Rather, “probe” is usedherein to describe the distal portion of the device which is extendedinto the intervertebral disc from the introducer.

[0121] The probe may optionally include functional elements whichperform different functions, such as transmitting energy and/or materialfrom a location external to the body to a location internal to the discbeing accessed upon. Alternatively, material can be transported in theother direction to remove material from the disc, such as removingmaterial by aspiration. The device allows the functional elements to becontrollably positioned and manipulated within the guided bymanipulation of the handle.

[0122] The probe is adapted to slidably advance through the introducerlumen, the probe having a distal section which is extendible through thedistal opening at the terminus of the introducer into the disc. Althoughthe length of the distal section can vary with the intended function ofthe device, as explained in detail below, a typical distance ofextension is at least one-half the diameter of the nucleus pulposus,preferably in the range of one-half to one and one-half times thecircumference of the nucleus.

[0123] In order that the functional elements of the probe can be readilyguided to the desired location within a disc, the distal section of theprobe is manufactured with sufficient rigidity to avoid collapsing uponitself while being advanced through the nucleus pulposus. The distalsection, however, has insufficient rigidity to puncture the annulusfibrosus under the same force used to advance the probe through thenucleus pulposus and around the inner wall of the annulus fibrosus.Absolute penetration ability will vary with sharpness and stiffness ofthe distal tip of the distal section, but in all cases, a probe of thepresent invention will advance more readily through the nucleus pulposusthan through the annulus fibrosus.

[0124] The inability of the distal section of the probe to pierce theannulus can be the result of either the shape of the distal tip of theprobe and/or the flexibility of distal portion. The distal tip isconsidered sufficiently blunt when it does not penetrate the annulusfibrosus but is deflected back into the nucleus pulposus or to the sidearound the inner wall of the annulus when the distal tip is advanced.Several novel distal tip embodiments are described herein.

[0125] 2. Design Features of Intervertebral Disc Devices

[0126] The devices according to the present invention comprise multiplenovel features including, but not being limited to (a) flexible necksadjacent the distal ends of the devices, (b) distal tips whichfacilitate navigation of the device within an intervertebral disc, (c)attachment mechanisms for the distal tips to the necks, (d) energydelivery mechanisms used with the devices for treating intervertebraldiscs, and (e) mechanisms for deploying the probe distal end within anintervertebral disc. Each of these different novel features aredescribed herein.

[0127] One feature of the probe employed in the device of the presentinvention is the inability of the distal section of the probe to piercethe annulus. This may be achieved either by the design of the neck ofthe probe, (i.e., the section of the distal section proximal to thedistal tip) or by the design of the distal tip of the probe. The designof the neck and distal tip of the probe can also be utilized tofacilitate navigation of the device within the intervertebral disc.

[0128]FIG. 3A shows a distal section 310 of a probe with a flexible neck312 which tapers from a proximal portion 314 of the distal section. Ablunt distal tip 316 is positioned on a distal end of the distal section310. Also illustrated is the distal end of an introducer 318 from whichthe probe distal section extends. It is noted that the probe distalsection is preferably retractable and extendable 320 relative to thedistal end of the introducer.

[0129]FIG. 3B illustrates a sequence which shows how the forwardadvancement of the distal section 310 of a probe from an introducer 318against tissue causes the probe to bend at the neck 312 relative to thelongitudinal axis 324 of the distal section 310. As illustrated in thesequence, further extension 320 of the probe against the tissue causesthe distal section 310 of the probe to bend further relative to thelongitudinal axis 324 of the distal section 310.

[0130] Rendering the neck flexible can be accomplished by using a seriesof different neck designs, any of which may be employed in the presentinvention. For example, FIG. 3C illustrates an embodiment where the neck316 is rounded. By employing a rounded neck 316, the distal sectionexhibits no predisposition with regard to in which direction the neckbends, as indicated by the arrows. Hence, by using a rounded taperedend, bending in any direction relative to the longitudinal axis of thedistal section can be achieved.

[0131] By contrast, FIG. 3D illustrates a neck 316 which has beenflattened on one side 322. Flattening the neck on one side causes thedistal section to be predisposed to bending in the plane perpendicularto the flattened surface toward the side of the flattened surface.Hence, by using a neck with a tapered end having one flat surface, theneck is predisposed to bend in a particular direction relative to thelongitudinal axis of the distal section.

[0132]FIG. 3E illustrates a neck 316 which has been flattened on twoopposing sides 324, 326. Flattening the neck the two opposing sidescauses the distal section to be predisposed to bending in planesperpendicular to the two flattened surfaces. If both flattened surfacesare parallel to each other, the neck will preferentially bend in thesame plane (as illustrated). If the two flattened surfaces are notparallel to each other, the neck will preferentially bend in the planeperpendicular to the first flattened surface or the plane perpendicularto the second flattened surface.

[0133]FIG. 3F illustrates a neck 316 where the neck is formed of a coil.The coil neck, like the rounded neck, allows the distal section to bendwith no predisposition with regard to in which direction the neck bends.Hence, by using a coiled neck, bending in any direction relative to thelongitudinal axis of the distal section can be achieved.

[0134] FIGS. 4A-4C illustrate a series of different distal tips whichmay be attached to the distal sections of the probes employed in thedevices of the present invention.

[0135]FIG. 4A illustrates a dome shaped distal tip 412 where the dome issymmetrical about the longitudinal axis of the distal section of theprobe. By having the tip be dome shaped, the tip has less resistancewhen being pushed through the nucleous pulposus. Meanwhile, by causingthe distal tip to be symmetrical, the distal tip does not introduce apredisposition for the distal section to bend in any particulardirection.

[0136]FIG. 4B illustrates an offset dome shaped distal tip 414 where thedome is asymmetrical about the longitudinal axis of the distal sectionof the probe. By causing the distal tip to be asymmetrical, the distaltip introduces a predisposition for the distal section to bend on theside of the tip where the tip is larger.

[0137]FIG. 4C illustrates a flat distal tip 416. By causing the distaltip to be flat, the resistance felt by the distal tip when pushedthrough the nucleous pulposus is enhanced. Optionally, although notshown, a predisposition for the distal section to bend in a particulardirection can be imparted by designing the distal tip to be asymmetricalrelative to the longitudinal axis of the distal section.

[0138] FIGS. 5A-5C illustrate a series of different distal tipattachment mechanisms which may be used to attach a distal tip to adistal section of a probe employed in the devices of the presentinvention. Each of these different distal tip attachment mechanismscauses the distal tip and the distal section of the probe to movethrough the dense colloidal material of the nucleous pulposus.

[0139]FIG. 5A illustrates an embodiment where the distal tip 512 and theneck 514 of the distal section is one unit made of the same material. Inthis embodiment, the distal tip is rigid relative to the neck 514 of thedistal section.

[0140]FIG. 5B illustrates an embodiment where the distal tip 512 and theneck 514 of the distal section are attached by a pivot mechanism 516,such as a ball and socket mechanism, which allows the orientation of thedistal tip to rotate relative to the neck 514.

[0141]FIG. 5C illustrates an embodiment where the distal tip 512 and theneck 514 of the distal section are attached by a spring 518. A springmechanism 518 not only allows the distal tip 512 to rotate relative tothe neck 514, the spring mechanism also allows the distal tip to bedistended away from the neck 514.

[0142] It is noted with regard to the neck, distal tip and attachmentmechanisms that any combination of the three may be used since it isanticipated that one may wish to alter the navigation behavior of theprobe within the nucleous pulposus by manipulating these threevariables.

[0143]FIG. 6 illustrates movement with bending of a distal section 612within nucleous pulposus 614 as the probe distal section is advancedwithin the intervertebral disc. Note that the introducer 620 remainsstationary as the probe is advanced. As can be seen, as the distalsection 612 is advanced, the distal tip 616 and neck 618 is bent awayfrom the intervertebral wall 622. This may be accomplished either bypredisposing the tip and/or neck to bending in a particular direction.It may also be accomplished by the wall itself having a certaincurvature. As the probe distal section is advanced, the distal sectionbends until the tension created by the bending exceeds the force that isbeing applied to the distal section by the tissue to cause the bending.Hence, the rigidity of the flexible distal section limits the amountthat the distal section ultimately bends.

[0144] FIGS. 7A-7C illustrate a sequence which shows how tissue forceresisting the forward advancement of the probe within the intervertebraldisc causes the distal section of the probe to bend. FIG. 7A shows aprobe 710 with an asymmetrical distal tip 712. As illustrated, theasymmetry of the tip causes more resistance to be applied to the largerside of the asymmetrical distal tip 712. As illustrated in FIG. 7B, theasymmetrical resistance causes the distal section of the probe to bend.As the distal section is advanced further, force begins to be applied tothe back of the distal tip, causing the distal section to bend further.As the distal section is advanced further, more force is applied to thedistal tip 712, as shown by the arrows in FIG. 7C against the distal tip712.

[0145] Referring back to FIG. 1E, the longitudinal axis of theintroducer 169 causes an element extended from the introducer 169 tohave a trajectory toward the center of the disc. However, it isdesirable to be able to deploy the probe and any functional elements onthe probe adjacent the internal wall 22 of the annulus fibrosus. FIGS.8A-8S illustrate a series of different embodiments for deploying thedistal section of the probe from the introducer so that the probeapproaches the internal wall of the annulus fibrosus.

[0146]FIG. 8A illustrates an embodiment where the distal end 812 of theprobe 814 is attached to the distal end of the introducer 816. Asillustrated in FIG. 8B, extension of the distal end 812 of the probe 814out of the distal end of the introducer 816 in this embodiment (denotedby the arrow) causes the probe to form a loop. Broadening of the loop byfurther extension of the probe causes the probe to encircle the internalwall 22 of the annulus fibrosus.

[0147]FIG. 8C illustrates another embodiment where the distal end 812 ofthe probe 814 is attached to the distal end of the introducer 816 via aguide wire lead 818. The guide wire lead 818 is thinner than the probe814 and thus can adopt a smaller radius of curvature than the probe 814.This allows a smaller bore introducer 816 to be utilized or a largerprobe 814 to be utilized since both the distal end of the probe and theguide wire lead can be more readily accommodated within the introducer.As illustrated in FIG. 8D, extension of the distal end 812 of the probe814 out of the distal end of the introducer 816 in this embodiment(denoted by the arrow) causes the probe to form a loop. Broadening ofthe loop by further extension of the probe causes the probe to encirclethe internal wall of the annulus fibrosus.

[0148]FIG. 8E illustrates another embodiment where the distal end of theprobe 814 forms a loop within the introducer where both sides of theprobe 814 are separately extendable and retractable relative to thedistal end of the introducer 816. As illustrated in FIG. 8F, extensionof the probe 814 out of the distal end of the introducer 816 in thisembodiment (denoted by the arrow) causes the probe to form a loop. Shownas boxes on the probe are a series of electrodes 820 for deliveringenergy to tissue within the disc. It is noted that other functionalelements can also be positioned on the probe. Broadening of the loop byfurther extension of the probe causes the probe to encircle the internalwall of the annulus fibrosus. Extending or retracting one side of theloop shaped probe causes the electrodes to move relative to the innerwall.

[0149]FIG. 8G illustrates another embodiment where a guide wire 824 isattached to the distal end of the introducer 816. The guide wire 824 isthinner than the probe 814 and thus can adopt a smaller radius ofcurvature than the probe 814. This allows a smaller bore introducer 816to be utilized or a larger probe 814 to be utilized since both thedistal end of the probe and the guide wire lead can be more readilyaccommodated within the introducer. As illustrated in FIG. 8H, extensionof the guide wire 824 out of the distal end of the introducer 816 inthis embodiment (denoted by the arrow) causes the guide wire 824 to forma loop. Broadening of the loop by further extension of the guide wire824 causes the guide wire 824 to encircle the internal wall of theannulus fibrosus. As illustrated in FIG. 81, a probe 814 may be extendedalong the guide wire 824 out of the distal end of the introducer. Theprobe 814 may include different functional elements for treating tissuewithin the disc.

[0150]FIG. 8J illustrates another embodiment where a guide wire 824forms a loop within the introducer where both sides of the guide wireloop 824 are separately extendable and retractable relative to thedistal end of the introducer 816. The guide wire 824 is thinner than theprobe 814 and thus can adopt a smaller radius of curvature than theprobe 814. This allows a smaller bore introducer 816 to be utilized or alarger probe 814 to be utilized since both the distal end of the probeand the guide wire lead can be more readily accommodated within theintroducer. As illustrated in FIG. 8K, extension of the guide wire 824out of the distal end of the introducer 816 in this embodiment (denotedby the arrows) causes the guide wire 824 to form a loop. Broadening ofthe loop by further extension of the guide wire 824 causes the guidewire 824 to encircle the internal wall of the annulus fibrosus. Asillustrated in FIG. 8L, a probe 814 may be extended along the guide wire824 out of the distal end of the introducer. The probe 814 may includedifferent functional elements for treating tissue within the disc.

[0151] FIGS. 8M-8O illustrate another embodiment of the embodiment shownin FIG. 8J where the guide wire 824 is capable of being folded uponitself. FIG. 8M illustrates the guide wire unfolded where section Aincludes a guide wire with a thin, concave shape section B includes atapered section that provides an area where the guide wire is foldedupon itself, and section C includes a rounded section such that therounded section fits within the concave shape of section A. FIG. 8Nshows the cross sections of guide wire sections A-C illustrated in FIG.8M. As illustrated in FIG. 8O, the guide wire may be folded upon itselfwhere the crease is at section B, and section A and section C cometogether. By having sections A and C fit together, the folded guide wirecan more readily be accommodated within an introducer.

[0152]FIG. 8P provides a sequence illustrating the deployment of theguide wire 824 from an introducer 816 within a disc such that the guidewire 824 encircles the internal wall 828 of the disc 830. As illustratedin the sequence, the crease allows the guide wire loop to be moretightly folded together. By then extending one side of the looped guidewire, a side of the guide wire can be expanded. Then, the other side ofthe guide wire loop may be expanded. The way in which sections A and Cfit together allow for the different sides of the loop to be separatelymoved relative to each other and extended and retracted from theintroducer.

[0153] It is noted that although FIGS. 8M-8P are described with regardto guide wires, that the probe may also be designed with a crease sothat it may be deployed in a similar manner as shown in FIGS. 8E, 8F andthen in FIG. 8P.

[0154]FIG. 8Q illustrates yet another embodiment where a guide wire 824and probe 814 are used in combination to deploy the probe 814 adjacentan internal wall 828 of a disc 830. As illustrated, an introducer 816 isintroduced into the disc. A guide wire 824 is then extended from theintroducer 816. The guide wire is predisposed to forming a loop whenextended from the introducer 816 and thus moves toward one side of thedisc. A probe 814 is then extended in combination with the guide wirefrom the introducer 816. The looped distal end of the guide wire 824serves to immobilize the distal end of the guide wire. This then allowsthe probe 814 to be expanded, thereby causing the probe to move alongthe wall of the disc.

[0155] It is noted with regard to the above embodiments that the distalportion of the probe and/or the guide wire may be pre-bent, if desired.“Pre-bent” or “biased” means that a portion of the probe, guide wire, orother structural element under discussion, is made of a spring-likematerial that is bent in the absence of external stress but which, underselected stress conditions (for example, while the probe is inside theintroducer), is linear. The un-stressed wire loop diameter preferablyhas a diameter between about 0.025-1 inch, more preferably between about0.05-0.75 inch, or most preferably between about 0.1-0.5 inch. Thediameter of the guide wire preferably has a diameter between about0.005-0.05 inch, more preferably between about 0.007-0.035 inch, or mostpreferably between about 0.009-0.025 inch. Such a biased distal portioncan be manufactured from either spring metal or super elastic memorymaterial (such as Tinel.RTM. nickel-titanium alloy, Raychem Corp., MenloPark Calif.). The introducer (at least in the case of a spring-likematerial for forming the probe) is sufficiently strong to resist thebending action of the bent distal end and maintain the biased distalportion in alignment as it passes through the introducer. Compared tounbiased probes, a probe or guide wire with a biased distal portionencourages advancement of the probe or guide wire substantially in thedirection of the bend relative to other lateral directions. Biasing theprobe or guide wire distal end also further decreases likelihood thatthe distal end of the probe or guide wire will be forced through theannulus fibrosus under the pressure used to advance the probe.

[0156] In addition to biasing the distal section of the probe or guidewire prior to insertion into an introducer, the distal section of theprobe or guide wire can be provided with a mechanical mechanism fordeflecting the distal section, such as a wire that deflects the distalsection in the desired direction upon application of force to theproximal end of the deflection wire. Any device in which bending of thedistal end of a probe or guide wire is controlled by the physician is“actively settable.” In addition to a distal section that is activelysettable by action of a wire, other methods of providing a bending forceat the distal section can be used, such as hydraulic pressure andelectromagnetic force (such as heating a shaped memory alloy to cause itto contract). Any of a number of techniques can be used to provideselective bending of the probe in one lateral direction.

[0157] Optionally, a sheath may be employed in combination with theprobe (or guide wire) to facilitate directing movement of the probewithin a disc. The sheath can be made of a variety of differentmaterials including but not limited to polyester, rayon, polyamide,polyurethane, polyethylene, polyamide and silicone.

[0158] FIGS. 9A-9C illustrate one embodiment where a sheath having apredefined curvature adjacent its distal end introduces curvature to aguide wire or probe extended from the sheath. FIG. 9A illustrates thedistal end of an introducer 912 with a sheath 914 and a probe 916extending from the introducer 912. It is noted that a guide wire couldbe used in place of the probe 916, the probe being later drawn over theextended guide wire.

[0159]FIG. 9B illustrates the sheath 914 being extend from the distalend of the introducer 912. As can be seen, the sheath 914 has apredefined curvature 918 adjacent its distal end. This curvature causesthe probe 916 (or guide wire) to likewise be curved. As illustrated inFIG. 9C, the sheath 914 is only extended a limited distance. Meanwhile,the probe is further extendable relative to the sheath 914. This allowsa degree of curvature to be maintained by the sheath at a known,reselected distance distal relative to the introducer. Meanwhile, theprobe 916 can be extended further out of the sheath. The probe itselfmay optionally have its own reselected degrees of curvature.

[0160] Since the purpose of the devices of the present invention is totreat tissue within an intervertebral disc by operation of the deviceadjacent to or inside the disc, one or more functional elements may beprovided in or on the distal section of the probe to carry out thatpurpose.

[0161] Non-limiting examples of functional elements include any elementcapable of aiding diagnosis, delivering energy, or delivering orremoving a material form a location adjacent the element's location inor on the probe, such as an opening in the probe for delivery of a fluid(e.g., dissolved collagen to seal the fissure) or for suction, a thermalenergy delivery device (heat source), a mechanical grasping tool forremoving or depositing a solid, a cutting tool (which includes allsimilar operations, such as puncturing), a sensor for measurement of afunction (such as electrical resistance, temperature, or mechanicalstrength), or a functional element having a combination of thesefunctions.

[0162] The functional element can be at varied locations on the distalsection of the probe, depending on its intended use. Multiple functionalelements can be present, such as multiple functional elements ofdifferent types (e.g., a heat source and a temperature sensor) ormultiple functional elements of the same type (e.g., multiple heatsources spaced along the intradiscal portion).

[0163] One of the possible functional elements present on the distalsection of the probe is a thermal energy delivery device. A variety ofdifferent types of thermal energy can be delivered including but notlimited to resistive heat, radiofrequency (RF), coherent and incoherentlight, microwave, ultrasound and liquid thermal jet energies. In theseembodiments, the electrode array length is preferably 0.2-5 inches long,more preferably 0.4-4 inches long, and most preferably 0.5-3 incheslong.

[0164] Some embodiments of the device have an interior infusion lumen.Infusion lumen is configured to transport a variety of different mediumsincluding but not limited to electrolytic solutions (such as normalsaline), contrast media (such as Conray meglumine iothalamate),pharmaceutical agents, disinfectants, filling or binding materials suchas collagens or cements, chemonucleolytic agents and the like, from areservoir exterior to the patient to a desired location within theinterior of a disc (i.e., the fissure). Further, the infusion lumen canbe used as an aspiration lumen to remove nucleus material or excessliquid or gas (naturally present, present as the result of a liquefyingoperation, or present because of prior introduction) from the interiorof a disc. When used to transport a fluid for irrigation of the locationwithin the disc, the infusion lumen is sometimes referred to as anirrigation lumen. Infusion lumen can be coupled to medium reservoirthrough the probe.

[0165] Optionally, one or more sensor lumens may be included. An exampleof a sensor lumen is a wire connecting a thermal sensor at a distalportion of the probe to control elements attached to a connector in theproximal handle of the probe.

[0166] Energy directing devices may also optionally be included, such asthermal reflectors, optical reflectors, thermal insulators, andelectrical insulators. An energy directing device may be used to limitthermal and/or electromagnetic energy delivery to a selected site of thedisc and to leave other sections of the disc substantially unaffected.An energy directing device can be positioned on an exterior surface ofthe distal section of the probe, as well as in an internal portion ofthe probe. For example, energy can be directed to the walls of a fissureto cauterize granulation tissue and to shrink the collagen component ofthe annulus, while the nucleus is shielded from excess heat.

[0167] Therapeutic and/or diagnostic agents may be delivered within thedisc via the probe. Examples of agents that may be delivered include,but are not limited to, electromagnetic energy, electrolytic solutions,contrast media, pharmaceutical agents, disinfectants, collagens,cements, chemonucleolytic agents and thermal energy.

[0168] In one embodiment, the device includes markings which indicate tothe physician how far the probe has been advanced into the nucleus. Sucha visible marking can be positioned on the handle or on the flexibletubing. Preferred are visible markings every centimeter to aid thephysician in estimating the probe tip advancement.

[0169] If desired, visible markings can also be used to show twistingmotions of the probe to indicate the orientation of the bending plane ofthe distal portion of the probe. It is preferred, however, to indicatethe distal bending plane by the shape and feel of the proximal end ofthe probe assembly. The probe can be attached to or shaped into a handlethat fits the hand of the physician and also indicates the orientationof the distal bending plane. Both the markings and the handle shape thusact as control elements to provide control over the orientation of thebending plane; other control elements, such as plungers or buttons thatact on mechanical, hydrostatic, electrical, or other types of controls,can be present in more complex embodiments of the invention.

[0170] Additionally, a radiographically opaque marking device can beincluded in the distal portion of the probe (such as in the tip or atspaced locations throughout the intradiscal portion) so that advancementand positioning of the intradiscal section can be directly observed byradiographic imaging. Such radiographically opaque markings arepreferred when the intradiscal section is not clearly visible byradiographic imaging, such as when the majority of the probe is made ofplastic instead of metal. A radiographically opaque marking can be anyof the known (or newly discovered) materials or devices with significantopacity. Examples include but are not limited to a steel mandrelsufficiently thick to be visible on fluoroscopy, a tantalum/polyurethanetip, a gold-plated tip, bands of platinum, stainless steel or gold,soldered spots of gold and polymeric materials with radiographicallyopaque filler such as barium sulfate. A resistive heating element or anRF electrode(s) may provide sufficient ratio-opacity in some embodimentsto serve as a marking device.

[0171] FIGS. 10A-10C illustrate a series of preferred designs forbipolar thermal energy delivery devices which may be used in combinationwith the devices of the present invention. It is noted that radiofrequency energy or resistive heating may be performed using thesedesigns.

[0172]FIG. 10A illustrates an embodiment where the thermal energydelivery device is a bipolar electrode comprising an active electrode1012 and a return electrode 1014 where the active electrode 1012 andreturn electrode 1014 are each spirally wrapped around a portion of thedistal section of the probe 1016. The probe is shown to be extendingfrom an introducer 1018. When a potential is introduced between theactive electrode 1012 and return electrode 1014, current flows throughthe tissue adjacent the two electrodes. Since the two electrodes arewrapped in a spiral about the active electrode, energy transfer isdistributed along the length of the probe, thereby more evenly heatingthe adjacent tissue.

[0173] It is noted that the distal section of the probe 1016 shown inFIG. 10A is predisposed to form a loop. By sizing the loop toapproximate the inner diameter of an intervertebral disc, it is possibleto cause the loop shaped probe to abut the internal wall of the disc.Then, by applying a potential between the electrodes, energy can besomewhat uniformly delivered to tissue adjacent the internal wall of thedisc. It is noted that over time, tissue interior to the loop may alsobe uniformly treated by the loop shaped electrode.

[0174]FIG. 10B illustrates another embodiment of a thermal energydelivery device. Like the embodiment shown in FIG. 10A, the distalsection of the probe 1016 is predisposed to form a loop. By sizing theloop to approximate the inner diameter of an intervertebral disc, it ispossible to cause the loop shaped probe to abut the internal wall of thedisc. As illustrated in FIG. 10B, an active electrode 1012 and a returnelectrode 1014 are positioned on opposing sides of the loop. By applyinga potential between the electrodes, energy can be delivered to tissuepositioned between the two electrodes.

[0175]FIG. 10C illustrates another embodiment of a thermal energydelivery device. Like the embodiment shown in FIGS. 10A and 10B, thedistal section of the probe 1016 is predisposed to form a loop. Asillustrated, a series of alternating active 1012 and return 1014electrodes are positioned along the distal section of the probe. Byapplying a potential between the series of active and return electrodes,energy can be delivered to tissue along the length of the probe.

[0176]FIGS. 11A and 11B illustrate yet another embodiment for a thermalenergy delivery device which may be used in combination with the devicesof the present invention. It is noted that radio frequency energy orresistive heating may be performed using these designs.

[0177]FIG. 11A illustrates an embodiment where a pair of probes whichform an active electrode 1112 and a return electrode 1114 extend from anintroducer or sheath 1116 and are spaced apart from each other. Byapplying a potential between the active and return electrodes, energycan be delivered to tissue along the length of the probes.

[0178]FIG. 11B illustrates a variation on the embodiment shown in FIG.11A where the pair of probes which form an active electrode 1112 and areturn electrode 1114 diverge from each other adjacent their distalends. By applying a potential between the active and return electrodes,energy can be delivered to tissue along the length of the probes. Byhaving the two probes diverge, a larger area of tissue may be treated.

[0179] Also shown in FIGS. 11A and 11B is a thermocouple 1118 forsensing temperature and a feedback loop 1120 for regulating thepotential between the electrodes in response to measurements by thethermocouple.

[0180] It is noted that other energy delivery devices may also be usedwith the intervertebral disc treatment devices of the present inventionbeyond those described with regard to FIGS. 10A-C and 11A-B, includingthose described in U.S. Pat. Nos. 6,135,999; 6,126,682; 6,122,549;6,099,514; 6,095,149; 6,073,051; 6,007,570; 5,980,504, which are eachincorporated herein by reference.

[0181] When the device is used as a resistive heating device, the amountof thermal energy delivered to the tissue is a function of (i) theamount of current passing through heating element, (ii) the length,shape, and/or size of heating element, (iii) the resistive properties ofheating element, (iv) the gauge of heating element, and (v) the use ofcooling fluid to control temperature. All of these factors can be variedindividually or in combination to provide the desired level of heat.Power supply associated with heating element may be battery based. Theprobe can be sterilized and may be disposable.

[0182] In some embodiments, thermal energy is delivered to a selectedsection of the disc in an amount that does not create a destructivelesion to the disc, other than at most a change in the water content ofthe nucleus pulposus. In one embodiment there is no removal and/orvaporization of disc material positioned adjacent to an energy deliverydevice positioned in a nucleus pulposus. Sufficient thermal energy isdelivered to the disc to change its biochemical and/or biomechanicalproperties without structural degradation of tissue.

[0183] Thermal energy may be used to cauterize granulation tissue whichis pain sensitive and forms in a long-standing tear or fissure.Additionally or alternatively, thermal energy is used to seal at least apart of the fissure. To do that, the disc material adjacent to thefissure is typically heated to a temperature in the range of 45-70degree C. which is sufficient to shrink and weld collagen. In onemethod, tissue is heated to a temperature of at least 50 degree C. fortimes of approximately one, two, three minutes, or longer, as needed toshrink the tissue back into place.

[0184] Delivery of thermal energy to the nucleus pulposus removes somewater and permits the nucleus pulposus to shrink. This reduces a“pushing out” effect that may have contributed to the fissure. Reducingthe pressure in the disc and repairing the fissure may help stabilizethe spine and reduce pain.

[0185] Global heating of the disc also can be used to cauterize thegranulation tissue and seal the fissure. In this embodiment of themethod, the heating element is positioned away from the annulus butenergy radiates to the annulus to raise the temperature of the tissuearound the fissure. This global heating method can help seal a largearea or multiple fissures simultaneously.

[0186]FIG. 12 shows an embodiment of the guide wire 1224 with amechanism 1235 at the end of the distal portion 1212 of the guide wirefor attaching the guide wire to the inner wall of the intervertebraldisc. By attaching the attachment mechanism to the inner wall,displacement of the guide wire is prevented during subsequent exchangeand withdrawal of other system components. The guide wire 1224 isextended into the intervertebral disc and navigated to a desired portionalong the inner wall of the disc. The attachment mechanism is insertedand held in place such that the distal portion 1212 is attached to theinner wall tissue. As illustrated in FIG. 12, extension of the probe1214 over the guide wire into the nucleus 120 of the intervertebral disccauses the probe to move along the path of the guide wire. Theattachment of the guide wire to the inner wall assists in keeping theguide wire in place despite force on the guide wire by the probe. In theinstance illustrated, the distal portion 1231 of the probe 1214 ispositioned at an annular fissure 44 for performing a function asdescribed herein. All publications and patent applications mentioned inthis specification are herein incorporated by reference to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

[0187] While the present invention is disclosed with reference topreferred embodiments and examples detailed above, it is to beunderstood that these examples are intended in an illustrative ratherthan limiting sense, as it is contemplated that modifications willreadily occur to those skilled in the art, which modifications will bewithin the spirit of the invention and the scope of the appended claims.Any patents, papers, and books cited in this application are to beincorporated herein in their entirety.

We claim:
 1. An intervertebral disc device comprising: a distal sheathsized to be extended from a distal end of an introducer that ispercutaneously delivered into an interior of an intervertebral disc, adistal section of the sheath being predisposed to adopting a bentconfiguration when extended from the introducer; a probe adapted to beextended from a distal end of the sheath, the bent section of the sheathcausing the probe to adopt a same bent configuration; and a proximalhandle for externally guiding the probe within an intervertebral disc.2. An intervertebral disc device according to claim 1 wherein a distalsection of the probe comprises a flexible neck which tapers in aproximal to distal direction, and a distal tip which is larger in crosssectional diameter than the flexible neck adjacent the distal tip, theflexible neck and distal tip serving to prevent the probe distal endfrom piercing an internal wall of the intervertebral disc.
 3. Anintervertebral disc device according to claim 2 wherein the flexibleneck is not predisposed to bending in any direction relative to alongitudinal axis of the probe.
 4. An intervertebral disc deviceaccording to claim 2 wherein the flexible neck is predisposed to bendingalong a single plane relative to a longitudinal axis of the probe.
 5. Anintervertebral disc device according to claim 2 wherein the flexibleneck is predisposed to bending in opposing directions along a singleplane relative to a longitudinal axis of the probe.
 6. An intervertebraldisc device according to claim 2 wherein the distal tip is symmetricalabout a longitudinal axis of the probe.
 7. An intervertebral disc deviceaccording to claim 2 wherein the distal tip is asymmetrical about alongitudinal axis of the probe.
 8. An intervertebral disc deviceaccording to claim 2 wherein the distal tip has a flat surfaceperpendicular to a longitudinal axis of the probe.
 9. An intervertebraldisc device according to claim 2 wherein the distal tip is attached tothe neck of the probe by a pivot mechanism.
 10. An intervertebral discdevice according to claim 2 wherein the distal tip is attached to theneck of the probe by a ball and socket mechanism.
 11. An intervertebraldisc device according to claim 2 wherein the flexibility of the neck ofthe probe causes the probe to bend and the distal tip to trail behind aportion of the probe as the probe is advanced through tissue within anintervertebral disc.
 12. An intervertebral disc device according toclaim 1 wherein a distal section of the probe comprising one or moreactive electrodes and one or more return electrodes which are positionedon the probe such that there are multiple pairs of an active band and areturn band of the active and return electrodes adjacent each otherpositioned longitudinally along the length of the distal section of theprobe, the electrodes being adapted to deliver bipolar electromagneticenergy to tissue within the intervertebral disc.
 13. An intervertebraldisc device according to claim 12 wherein the distal section of theprobe is predisposed to forming a loop.
 14. An intervertebral discdevice according to claim 1 wherein a distal section of the probe ispredisposed to forming a loop when extended from the distal end of theintroducer, the looping portion of the probe comprising an activeelectrode and a return electrode which are positioned on the probe suchthat the active and return electrodes are on opposing sides of the probeloop.
 15. An intervertebral disc device according to claim 1 wherein adistal section of the probe comprises separate active and returnelectrode elements which are predisposed to bending away from each otherwhen extended from the distal end of the introducer.
 16. Anintervertebral disc device comprising: a distal sheath sized to beextended from a distal end of an introducer that is percutaneouslydelivered into an interior of an intervertebral disc, a distal sectionof the sheath being predisposed to adopting a bent configuration whenextended from the introducer; a guide wire adapted to be extended from adistal end of the sheath, the bent section of the sheath causing theguide wire to adopt a same bent configuration; a probe adapted to beextended from a distal end of the sheath over the guide wire, the bentsection of the sheath causing the probe to adopt a same bentconfiguration; and a proximal handle for externally guiding the probewithin an intervertebral disc.
 17. An intervertebral disc deviceaccording to claim 16 wherein a distal section of the probe comprisingone or more active electrodes and one or more return electrodes whichare positioned on the probe such that there are multiple pairs of anactive band and a return band of the active and return electrodesadjacent each other positioned longitudinally along the length of thedistal section of the probe, the electrodes being adapted to deliverbipolar electromagnetic energy to tissue within the intervertebral disc.18. An intervertebral disc device according to claim 17 wherein thedistal section of the probe is predisposed to forming a loop.
 19. Anintervertebral disc device according to claim 16 wherein a distalsection of the probe is predisposed to forming a loop when extended fromthe distal end of the introducer, the looping portion of the probecomprising an active electrode and a return electrode which arepositioned on the probe such that the active and return electrodes areon opposing sides of the probe loop.
 20. An intervertebral disc deviceaccording to claim 16 wherein a distal section of the probe comprisesseparate active and return electrode elements which are predisposed tobending away from each other when extended from the distal end of theintroducer.